Efficacious adjuvant treatments such as radiotherapy following breast conserving surgery, and chemo- or hormonal therapy for stage 1b or 2 breast cancer improve disease-free and overall survival. Lower rates of radio-therapy following breast conserving surgery have been reported among black women. Few data exist about racial disparities in receipt of chemo- or hormonal therapies; however, poorer stage-specific survival rates among blacks and among women with poor or no insurance suggests underuse of these treatments. Despite elimination of racial disparities in rates of mammography screening, the full benefit of screening will not be realized unless underuse of effective treatments or ways to increase treatment rates. Our preliminary work suggests omitted referrals and lack of follow-up tracking account for a majority of underuse particularly among minority patients. The proposed breast cancer project will measure the extend of underuse of efficacious breast cancer treatments among patients of the hospitals serving East and Central Harlem and other minority communities in lower Manhattan. We will first interview physicians and patients about their reasons for omissions of efficacious adjuvant treatments. At the 7 participating hospitals, we will then implement an intervention consisting of: a) computerized reminders to prompt surgeons to refer patients for adjuvant treatment, and b) an individual to track referrals for and receipt adjuvant treatments. We will assess racial/ethnic differences in rates of underuse and explore racial differences in reasons for underuse. We will assess the impact of the intervention on reducing underuse of efficacious therapies among 2 years of 695 pre-intervention and 2 years of 695 post-intervention patients. This study will provide new knowledge about racial disparities in treatment for early-stage breast cancer; patient and physician reasons for underuse; and the effectiveness of a simple, sustainable intervention to improve rates of efficacious cancer treatment.